researchtoolssurveys DNSFactory

DNS SURVEYS

Open Resolvers

An ongoing survey that searches for open DNS resolvers.

Cache Poisoners

An ongoing survey that searches for DNS cache poisoners.

April 2005: Number of Nameservers

We probed 5% of routed IPv4 space, or 70 million addresses, looking for nameservers. For those that replied, we also tried to determine their software and version.

Zone and Nameserver Statistics
  • October 2009
  • October 2008
  • October 2007
  • August 2006
  • June 2005 With these surveys we send queries to 1,000,000+ zones and their authoritative nameservers looking for zones and nameservers that:

    • Advertise their software version
    • Allow recursion
    • Allow zone transfers
    • Exist on the same subnet
    • Have delegations which differ from authoritative NS records
    • Have lame delegations
    • Have questionable SOA values
    • Have mismatched serial numbers
    • Utilize IPv6
    • Utilize DNSSEC
    • Publish SPF records

    We also query a random 5% sample of routed IP addresses to look recursive resolvers and determine whether or not they openly provide service to anyone, and what software they are running.


© 2009 The Measurement Factory.